For geographers, the U.S. Geological Survey is "the show." The headquarters in Reston, Virginia (a town whose invention I remember from my childhood) is the fount of beautiful and authoritative maps. The USGS staff in the field make those maps and do a remarkable variety of research into hydrology, fire, biodiversity, and much more.
One interesting thing I learned about USGS staff (at least in hydrology) is that they tend to be very good at English/metric conversions. I am pretty good at it, but these people are amazing. As scholars, they publish their research in metric units, but as U.S. government officials, they have to use the archaic inches and miles stuff.
The geography section of the USGS web site provides updates on recent science, links to various mapping resources and earth imagery, and links to the regional science research centers of the agency.